There are existing telephone services, typically 1-800 numbers, which provide a dialing tone in response to an incoming call from any one of a typically large population of subscribers. The caller then dials a telephone number of a desired subscriber and is connected to that subscriber. These services are available either through PABX's or as a Centrex service. The caller must provide the telephone number of the desired subscriber and cannot request that the telephone number be provided in response to provision of other information such as the subscriber name.
Telephone network operators, such as cellular telephone network operators and long-distance operators provide a voice-assisted dialing system which is trained by each of a plurality of callers to contact a limited number of subscribers upon receipt of oral identification of a desired subscriber.
In corporate voice-mail systems, it is possible to enter a dialogue menu in which the caller is prompted to provide a touch-tone identification of a desired extension within the local PABX.
There are audio/telephony add-on cards, such as the IBM M-Wave, which allow a telephone to be employed as an instrument for providing audio input to a computer and for receiving audio output therefrom.